We study a problem concerning the compulsory behavior of the solutions of systems of discrete equations u(k + 1) = F(k, u(k)), k ∈ N(a) = {a, a + 1, a + 2 }, a ∈ N,N= {0, 1,... } and F : N(a) × R^...We study a problem concerning the compulsory behavior of the solutions of systems of discrete equations u(k + 1) = F(k, u(k)), k ∈ N(a) = {a, a + 1, a + 2 }, a ∈ N,N= {0, 1,... } and F : N(a) × R^n→R^n. A general principle for the existence of at least one solution with graph staying for every k ∈ N(a) in a previously prescribed domain is formulated. Such solutions are defined by means of the corresponding initial data and their existence is proved by means of retract type approach. For the development of this approach a notion of egress type points lying on the defined boundary of a given domain and with respect to the system considered is utilized. Unlike previous investigations, the boundary can contain points which are not points of egress type, too. Examples are inserted to illustrate the obtained result.展开更多
基金supported by the Grant 201/04/0580 of the Czech Grant Agency(Prague)by the Grant No 1/0026/03 and No 1/3238/06 of the Grant Agency of Slovak Republic(VEGA)
文摘We study a problem concerning the compulsory behavior of the solutions of systems of discrete equations u(k + 1) = F(k, u(k)), k ∈ N(a) = {a, a + 1, a + 2 }, a ∈ N,N= {0, 1,... } and F : N(a) × R^n→R^n. A general principle for the existence of at least one solution with graph staying for every k ∈ N(a) in a previously prescribed domain is formulated. Such solutions are defined by means of the corresponding initial data and their existence is proved by means of retract type approach. For the development of this approach a notion of egress type points lying on the defined boundary of a given domain and with respect to the system considered is utilized. Unlike previous investigations, the boundary can contain points which are not points of egress type, too. Examples are inserted to illustrate the obtained result.